All Zach Sobiech wanted to do was to say goodbye to his family and friends.

In the process of doing that, the 17-year-old has inspired, exhilarated, touched and entertained hundreds of thousands of people, moving some of them to tears and motivating others to change their lives.

Told that a rare form of bone cancer has likely left him with only a few months to live, the Stillwater High School senior wrote a song titled "Clouds" in which he bids farewell to the people around him. "Maybe someday I'll see you again," he sings. "We'll fly up in the clouds and we'll never see the end."

The song, begun as a basic recording on his cellphone, has worked its way up to a professional studio version that has been accessed by more than a million YouTube users and is available for download on iTunes. The song's success mystifies its creator.

"I don't know why so many people care about it," he said. "I know why it's special to me, but I didn't think it would be special to others."

Sobiech, who lives in Lakeland, has been flooded with requests for media interviews. Stories about him have appeared everywhere from Billboard magazine to the United Arab Emirates Press. A week ago, a CNN camera crew followed him around school.

WAYS TO HEAR 'CLOUDS'

The crazy part, many would say, is that being an overnight sensation hasn't had any effect on him -- beyond the fact that he sometimes notices "more girls smiling at me."

"Sometimes we'll give him a little punch in the arm" when his friends see that happening, said Sammy Brown, a fellow Stillwater senior who teams up with him in a musical duo called the Firm Handshake. "We kid him that we're just trying to keep him level-headed, but it really hasn't changed him at all."

Then again, he didn't change after getting the diagnosis of osteosarcoma, which was discovered in 2009 when he was hobbled by pain in his left hip. He didn't change through multiple surgeries and months of chemotherapy. And he didn't change when he was told that the cancer had spread to the point that the best that doctors could hope for was to slow the disease's progression.

Before any of this happened, Sobiech was upbeat, optimistic and fun. And he still is.

"As Zach fights to live, he remains the same joyful soul he has always been," his family says on his Caring Bridge site. "He still smiles as brightly as he did before cancer -- it just means more now."

The proof of Sobiech's character is his selflessness, said Dan Seeman, VP/marketing manager for KS95 and the man who helped arrange for the professional studio recording of "Clouds." Sobiech is selling a CD of his music that includes "Clouds," with all the money -- more than $30,000 raised since Dec. 6 -- going to fund research of osteosarcoma, which typically occurs in teens and adolescents.

"If there ever was a family that could say 'It's all about us,' this is the one," Seeman said. "But, no, it's about every other kid who faces this problem."

A musical prescription

Sobiech said that writing "Clouds" was his natural reaction when he got the bad medical news.

"There are two ways you can go at a time like that," he said. "You can cry, or you can talk about it. I'm the type of person who talks about it."

The comments people have posted on YouTube spell out the ways "Clouds" has affected them. A woman who recently lost her grandmother to cancer thanks him for his "healing song." A wounded Iraqi war veteran says it has motivated him to quit feeling sorry for himself, and countless others write about how seeing how Sobiech is handling his situation has given them the strength to deal with the problems they face.

"Your song made me think about the life I'm living," one admirer wrote. Another said: "If this doesn't reach your heart, you don't have one." And yet another added: "Thank you for being here in this moment Zach and sharing your heart with the world. Shine on Zach, sing on, and mainly, live on."

Sobiech appreciates the feedback.

"The ability to touch someone through my music is amazing," he said. "I know what the song meant to me, but to have it mean something to other people is really, really cool."

The song's skyrocketing popularity is a result of more than its background, Seeman said.

"Yes, the story behind it is poignant and touching and moving," he said. "But beyond that, it's a good song. The key to all this is that the music is good."

After originally recording the song on his cellphone, Sobiech played it for his guitar teacher, who had him record it again on equipment he keeps in his home. Seeman, who was in the process of arranging KS95's annual cancer-research radiothon, heard that version and called a friend, pianist John Lynn. Within 24 hours, Lynn had rounded up a group of professional musicians who were willing to donate their talents, and Minneapolis-based Atomic K Records offered to provide free studio time. The resulting version is the one on YouTube and iTunes.

Happy, not sad

The song reflects Sobiech's sunny personality, Brown said.

Despite the subject matter, "what comes out is hopeful," she said. "It's upbeat."

Sobiech has his down moments, he admits. They often happen when the reality of his situation hits him by surprise. For instance, the first day of school when the seniors were warned not to coast through their final year if they planned to go to college.

"I faced a decision: Am I going to work on school or work on living my life?" he said. "I told my teachers that I probably wasn't going to be doing my homework, that I was going to concentrate on having fun and working on my music. They understood."

He laughs when he describes his creative style. He writes the lyrics first, usually in the form of a poem, "which is ironic, because I took a poetry class in junior high and hated it. I thought it was the stupidest thing in the world."

He's hoping to come up with enough songs to fill another CD, but he knows better than anyone that the future is not guaranteed.

"I'm working as hard as I can to produce quality material," he said. "I'm going to keep moving forward with music."